Electric fuse.



Max

T. E. MURRAY, JR. ELECTRIC FUSE. APPLICATION FILED APR. 22, 1912.

- Patented Dec. 31, 1912.

THOMAS E. MURRAY, .m., or NEW xonx, N. Y.

nnncrnrc FUSE.

Specification of Letters Patent.

Patented Dec. 31,1912.

Application filed April 22, 1912. Serial No. 692,259.

To all whom it may concern:

Be it known that I, THOMAS E. MURRAY, Jr., a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented a certain new and useful Improvement in Electric Fuses, of which the following is a specification.

section.

' The invention relates to electric fuses. As

such fuses are commonly constructed, the circuit connections are attached to the plug, casing or other support for the strip, and arranged so that a new strip can be substituted for a strip which has blown. Where the explosion not only destroys the strip, but also melts or injures the circuit terminals, it is obviousthat not only a new fuse strip but a new support or plug must be provided.

My invention has for its object to localize the blowing of the fuse to a predetermined fractional part of the fuse strip itself, and thus to prevent the destructive effect of the explosion from extendin to said circuit terminals to which the strip is connected at its on s.

My invention consists in a fuse strip, to which the circuit terminals are connected, disposed in contact with two bodies of nonpulverulent refractory insulating material, which extend from the circuit terminals over fractions of the length of the strip, so that an uncovered portion of the strip is exposed between them. By this means, the

blowin of the fuse is localized to the uncovere portion, and the terminals are protected. Preferably, the protecting bodies are of asbestos or other flexible fabric.

In the accompanying drawings-Figure 1 is a 'view of my fuse, with the protective envelop in lace. Fig. 2 is a longitudinal 1g. 3 is a view of the fuse, with the protective envelop removed. Fig. 4 is I a cross section.

V Similarletters of reference indicate like parts.

The fuse stripA-ds preferably made with the usual contraction B in its middle portion, and with its ends doubled over and perforated for the convenient attachment of the circuit terminals C, Fig. 2. Extending from each circuit terminal and enveloping the strip is a wrapping D, D of asbestos or other refractory insulating material. A portion E of the strip between the ends of the wrappings is left exposed. The wrap plugs are secured in place by a Winding F,

of cord, or in any other suitable way. By reason of this construction, the blowing of the fuse-is caused to occur in the exposed portion E, and its destructive effect does not extend beyond a short distance inward from the ends of the wrappings D. Hence said effect does not reach the terminals C.

I am-awarethat a fuse strip has been disposed in a case filled with powdered lime or thelike, and passed through a paper drum embedded in said lime, so that an air space is formed around the middle portion of the strip. By my construction, the fuse case,

the pulverulent filling and the paper drum are all done away with and a complete fuse,

affording ample protection to its circuit terminals and which may be exposed to the atmosphere without any further covering, 1s obtained by simply applying the refractory material to the strip and its terminals,

as herein set forth, the device bein'g exposed to the atmosphere.

I claim:

1. A fuse strip, circuit terminals connected thereto, and two exposed. envelops of refractory insulating material respectively covering a fraction of the length of said strip and respectively in contact with said circuit terminals.

2. A fuse strip, circuit terminals con nected thereto, and two exposed wrappings of flexible refractory insulating material respectively covering fractions of the length of said strip and respectively in contact with said circuit terminals.

In testimony whereof I have afiixed my signature in presence of 'twowitnesses.

THOMAS E. MURRAY, J R. Witnesses:

Gnn'rnnna T. PORTER, MAI T. MOGARRY. 

